Front frame for a cascade thrust reverser structure

Abstract

The present disclosure relates to a front frame for an aircraft nacelle comprising a turbojet mounted on a suspension strut, said nacelle comprising a thrust reverser including an actuator designed to open a thrust reversal cowling. The front frame comprises a tubular torsion box, a first straight attachment edge intended to attach the box to a turbojet casing and a second straight attachment edge intended to attach the box to air flow diversion means. The front frame is arranged to transmit tensile and compressive loads between the turbojet casing and the air flow diversion means and torsion loads absorbed by the suspension strut. The front frame is characterized in that the tubular torsion box has a semi-elliptical or elliptical cross-section.

What is claimed is: 
     
       1. A front frame for an aircraft nacelle comprising a tubular shaped torsion box, a first straight attachment edge attaching said tubular shaped torsion box on a turbojet engine casing and a second straight attachment edge attaching said tubular shaped torsion box to air flow cascade vanes, said front frame being arranged to transmit tensile and compressive loads between a turbojet engine casing and the air flow cascade vanes and torsion loads absorbed by a suspension mast wherein the tubular torsion box has a semi-elliptical or elliptical cross-section and the first straight attachment edge and the second straight attachment edge project outwardly from an outer circumference of the tubular torsion box and form a single integral part with the tubular torsion box, and further comprising cross stiffeners connecting a portion of the outer circumference of the tubular torsion box and the first straight attachment edge. 
     
     
       2. The front frame according to  claim 1 , wherein the first and second straight attachment edges are diametrically opposite with respect to the box so as to transmit the tensile loads between the turbojet engine casing and the air flow diverting means. 
     
     
       3. The front frame according to  claim 1 , wherein the front frame comprises a straight structure comprising the first and second edges so as to transmit the tensile loads between the turbojet engine casing and the air flow diverting means. 
     
     
       4. The front frame according to  claim 3 , wherein the tubular torsion box having a semi-elliptical shaped section, said straight structure forms the basis of the semi-ellipse. 
     
     
       5. The front frame according to  claim 4 , wherein the tubular torsion box has a semi-circular shaped section. 
     
     
       6. The front frame according to  claim 3 , wherein the tubular torsion box shape having an elliptical shaped section, said straight structure passes through the box. 
     
     
       7. The front frame according to  claim 6 , wherein the tubular torsion box has a circular shaped section. 
     
     
       8. The front frame according to  claim 1 , wherein the torsion box comprises a core coated with a composite material. 
     
     
       9. The front frame according to  claim 8 , wherein the torsion box is integrally made of composite material. 
     
     
       10. The front frame according to  claim 1 , wherein the front frame comprises a wall to attach said torsion box to a middle section of the nacelle, said wall forming a part integral with the torsion box. 
     
     
       11. A nacelle including a thrust reverser fitted with a front frame according to  claim 1 .